3870989

Information

• Patent Grant
• 3870989

• References
• Source

• Patent Number

  3,870,989

• Date Filed

  Not available

• Date Issued

  Tuesday, March 11, 1975
  50 years ago

• CPC

  • H04B11/00 - Transmission systems employing sonic, ultrasonic or infrasonic waves
  • G01S1/02 - using radio waves
  • G01S1/72 - using ultrasonic, sonic or infrasonic waves
  • G01S3/8036 - derived directly from separate directional systems

• US Classifications

  • 367 - Communications, electrical: acoustic wave systems and devices